1. Field of the Invention
The present invention relates to an abnormality determining apparatus that determines an abnormality in a detection subject, based on obtained results of a plurality of types of information of the detection subject different from each other, and a set information group, which is an aggregate of combination of various types of information stored in an information storage unit.
The invention also relates to an abnormality determining apparatus that determines whether there is an abnormality in the detection subject, based on a detection result of a tone detector that detects tone, i.e., sound, generated from the detection subject. Furthermore, the invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine equipped with such an abnormality determining apparatus.
The invention also relates to an image forming apparatus that forms an image such as an ink image and a toner image on a recording medium such as recording paper, for example, a copying machine, a printer, and a facsimile machine. Furthermore, the invention relates to an information obtaining method for obtaining electronic information stored in the information storage unit of the image forming apparatus.
2. Description of the Related Art
Conventionally, if an apparatus fails users cannot use the apparatus until it is repaired. Accordingly, it is need of a technology to predict whether an apparatus is going to fail before it fails.
On the other hand, various methods have been known in which a plurality of types of information is obtained from a detection subject when the detection subject is in a normal state, to construct a normal data group, and thereafter, the degree of normality of the detection subject is measured based on the normal data group and information obtained from the detection subject. For example, one of the methods is the Maharanobis Taguchi System (MTS) method described in “Technical Developments in the MT system” (by Genichi TAGUCHI, chairman of the publication group, published by Japanese Standards Association). According to the MTS method, set information including a plurality of types of information is first obtained from the detection subject in the normal state. Pieces of set information are then collected to construct the normal data group. Thereafter, when it is desired to check the degree of normality of the detection subject, various types of information are obtained from the detection subject. A Maharanobis distance, which indicates the relative position of the set information in a multidimensional space of the normal data group constructed beforehand, is then determined, and based on the result, the degree of normality of the detection subject is measured. By using the MTS method, slight abnormality of a machine or an apparatus as the detection subject can be detected, and the occurrence of a failure can be predicted beforehand.
However, as in the MTS method, when the presence of abnormality in a machine or an apparatus is determined by using the normal data group constructed beforehand, there is a problem, depending on the obtaining method of the normal data group, in that the determination accuracy is degraded or there is a cost increase. For example, it is assumed here that a certain type of machine product is manufactured in a factory, which is equipped with an abnormality determining apparatus that determines the presence of abnormality by using the MTS method. To determine the presence of abnormality in the product by the abnormality determining apparatus, it is necessary to store the normal data group. However, the normal data group has not been obtained from the just finished product. Therefore, if the time-consuming work to make a trial run of the product for a predetermined period to obtain the normal data group is carried out for each product, a cost increase occurs due to the work. To avoid such a cost increase, if the normal data group is obtained beforehand from a standard machine of the product, the determination accuracy is degraded since there is a specific normal data range in the individual product due to an assembly error of parts or the like, even if the normal data group is obtained from the standard machine of the same standard.
When the presence of abnormality in the detection subject is determined by using the normal data group constructed beforehand as in the MTS method, to increase the determination accuracy as much as possible, it is necessary to construct the normal data group in the following manner. That is, a trial run of the detection subject in the normal state is made under various conditions, to obtain data under conditions as many as possible.
On the other hand, when the integrity of products under development is matured and mass production becomes possible, it is desired to supply the products to the market as soon as possible, from the standpoint of return on investment. However, in many cases, sufficient amount of normal data group has not yet been collected for the products, whose mass production has just been possible. Accordingly, when the presence of abnormality in the products is determined by the abnormality determining apparatus, if supply to the market is hastily done, the determination accuracy can be degraded.
Therefore, the present inventors are currently developing an abnormality determining apparatus that constructs the set information group by obtaining the set information including a plurality of types of information from the product, during the initial operation period of the product after factory shipment. The set information group including various types of set information obtained from the product during the initial operation period, which has high possibility of normal state, can be used as the normal data group used at the time of determining the presence of abnormality. Accordingly, even if a sufficient amount of normal data group has not yet been stored at the time of factory shipment, determination accuracy can be increased by supplementing the data at a shipment destination.
However, in the limited period such as the initial operation period, users do not always use the products under various conditions. The product is used only under a particular condition corresponding to user's preference or the installed environment of the product, for example, in the case of an image forming apparatus, such that the image forming apparatus is frequently used in a high resolution mode at a relatively slow image forming speed. In such a case, the sufficient amount of normal data group cannot be supplemented during the initial operation period.
Furthermore, if a failure occurs in various machines and apparatuses on the market, conventionally, users cannot use the machine or apparatus until the repair has been completed, depending on the content of the failure, which is inconvenient for users. Accordingly, it is desired to find the abnormality in the machine or apparatus at an early stage and handle the failure, to suppress the occurrence of failures and reduce the down time.
On the other hand, various types of abnormality determining apparatuses that determine the presence of abnormality in a detection subject based on a detection result of tone generated from a machine or apparatus as the detection subject have been proposed (see for example, Japanese Patent Application Laid-open No. H10-19662, Japanese Patent Application Laid-open No. 2000-216943, and Japanese Patent Application Laid-open No. 2001-92688).
The present inventors are currently developing an image forming apparatus that determines the presence of abnormality based on a detection result by a vibration detector, to reduce the down time. This image forming apparatus forms an image according to the electrophotographic method in which an electrostatic latent image formed on the surface of a photoconductor, which is a latent image carrier, is developed by a toner to form a visual image, which is then transferred to a transfer body such as transfer paper from the photoconductor. In the image forming apparatus having such a configuration, if the residual toner adhering on the photoconductor surface after having passed through a transfer process is cleaned by a cleaning blade, the cleaning blade deteriorated due to wear can be a cause of various troubles. Accordingly, in the image forming apparatus under development, a vibration detector is fixed to the cleaning blade, so that abnormality in the cleaning blade and around thereof can be detected at an early stage, based on the detection result of vibrations.
In the image forming apparatus under development, if the fixed state of the vibration detector with respect to the cleaning blade varies for each apparatus due to a difference in thickness of an adhesive for fixation, an error occurs in the vibration detection result, thereby decreasing the abnormality determination accuracy. Furthermore, if an abnormal state occurs in a place relatively away from the fixed position of the vibration detector, it is difficult to detect abnormal vibrations by the vibration detector.
On the other hand, in the abnormality determining apparatus that determines the presence of abnormality based on the tone, since a difference in the fixed state of the tone detector hardly affects the detection of the tone, a decrease in the determination accuracy hardly occurs due to the difference. Furthermore, even an abnormal state occurring in a place relatively away from the tone detector can be detected based on the tone detected by the tone detector.
However, various types of tones generated by machines and apparatuses include a tone that changes the state with a change in the temperature, the humidity, and the composition in the air. For example, if a frictional resistance at a contact portion between the cleaning blade and the photoconductor changes due to a change in the temperature and the humidity, the state of tone generated from the contact portion also changes. Thus, if the state of tone changes with environmental variation, it is difficult to determine the presence of abnormality accurately based on the tone.
The present inventors have found that there is the possibility that the normal data group becomes not suitable for performing accurate determination according to circumstances, in the process of developing the abnormality determining apparatus that determines the presence of abnormality in the image forming apparatus by using the MTS method.
For example, in the information obtained from the image forming apparatus, there is one having the normal value different between the summer containing high humidity and the winter containing less humidity. If such information is included as a part of the normal data group, the normal data group becomes unsuitable for determination of abnormality in the summer or in the winter, corresponding to the obtaining period of the information. Furthermore, there is information in which the normal value changes between a plurality of detection subjects, for which the production lots are different from each other, although the reason is not known. If such information is included as a part of the normal data group, the normal data group becomes unsuitable for the image forming apparatus to be detected, in the determination of abnormality with respect to an image forming apparatus as the detection subject in a production lot different from the image forming apparatus, whose information has been obtained.
Conventionally, as a system useful for management companies which offer maintenance service of the image forming apparatus, an image forming apparatus service system (hereinafter, simply “service system”) described in Japanese Patent Application Laid-Open No. 2003-215986 is known. When a transitory severe abnormality that cannot be handled by the user such as a severe paper jam occurs in the image forming apparatus, the service system notifies the occurrence to the management company through a communication line such as a phone line. The management company can quickly dissolve the transitory severe abnormality having occurred in the image forming apparatus, by dispatching a maintenance person to the user based on the notification.
The abnormality occurring in the image forming apparatus includes a transitory slight abnormality such as a slight paper jam that can be easily removed by the user, in addition to the transitory severe abnormality. Furthermore, there is a chronic slight abnormality continuously causing a phenomenon different from the normal state, due to deterioration progress of parts, although it does not show a noticeable phenomenon that can be easily recognized. The abnormality occurring in the image forming apparatus further includes a phenomenon, that is, such a failure that the image forming apparatus suffers a fatal damage so that the apparatus cannot be normally operated, resulting from further progress of deterioration of parts, which is a slight abnormality in which unrecognizable phenomenon occurs, for example, difference in paper feed timing relatively increases. Among these abnormalities, the transitory severe abnormality can be dissolved quickly by dispatching the maintenance person to the user, and the transitory slight abnormality can be dissolved quickly by the user without requesting a dispatch of the maintenance person. On the other hand, the chronic slight abnormality resulting from deterioration of parts does not show a noticeable phenomenon that can be easily recognized, therefore, it is left as it is without noticing the problem. Accordingly, if a failure occurs, long time is required for arrangement for renewal parts, thereby causing inconvenience.
Accordingly, the present inventors are currently developing an abnormality determining method that uses a statistical method such as the Maharanobis Taguchi System (MTS) method described in “Technical Developments in MT system” to find the chronic slight abnormality promptly, and predicts an occurrence of a failure beforehand. According to the MTS method, set information including a plurality of types of information, for example, linear velocity information of the photoconductor, information relating to whether the image forming apparatus is set to a high-speed print mode, and output color number information, is obtained from the detection subject in the normal state. The set information is collected for each time series from a detection subject clearly having no abnormality, for example, immediately after factory shipment or maintenance, to construct the normal data group formed of an aggregate of pieces of set information. Thereafter, when it is desired to check whether the detection subject is normal, the set information is obtained again from the detection subject. The Maharanobis distance, which indicates the relative position of the set information in the multidimensional space of the normal data group constructed beforehand, is determined for the pieces of information, and based on the result, the degree of normality of the detection subject is measured. By using the MTS method, an occurrence of the chronic slight abnormality in the image forming apparatus as the detection subject can be found quickly, and the occurrence of a failure can be predicted beforehand.
As in the MTS method, when the presence of a chronic slight abnormality is determined by using the normal data group constructed beforehand, it is necessary to obtain the set information as many as possible from the apparatus in the normal state, prior to the determination. To do this, it is desired to add the set information to the normal data group in the following manner. That is, set information obtained under the normal operation state during a period since the start of initial operation immediately after factory shipment until a predetermined period has passed is respectively obtained from a plurality of image forming apparatuses operating at the individual user, and the pieces of information are added to the normal data group.
It is assumed to adopt a configuration such that the set information stored in the user's image forming apparatus is automatically sent to the management company regularly via the communication line, to realize the addition of data. The user may have a concern, for example, not only the set information but also information of a FAX number list and copy image data of confidential documents can be automatically sent, thereby leaking the individual information and confidential information. Furthermore, even if such a method is adopted that when the maintenance person visits the user's place, the set information stored in the apparatus is obtained from a terminal connected to the image forming apparatus, the user may have a similar concern.
Conventionally, the maintenance service has been offered to improve the image forming apparatus after shipment, such that the maintenance person dispatched to the user connects a terminal to the image forming apparatus to update the control program of the apparatus. At this time, the user may have a similar concern.